Saturday, June 1, 2013

India's own GPS network takes shape

About 40 Km from the IT hub city of
Bengaluru in south India, lies a remote hamlet known as “Byalalu.”
Travelling on Bengaluru-Mysore highway, one needs to take a right
turn in Kumbalgod Industrial area and then proceeding on a rather
bumpy road, he can reach this sleepy hamlet with plain farm land
dotted around and a typical rural setting. Readers are likely to ask
a question as to why in the first place any one would like to travel
to Byalalu?

Located just in the vicinity of this
hamlet, only about a Km away, is India's principal communication
centre for spacecraft known as deep space network. Even a casual
visitor to this area would not fail to see huge white dish antennas
directed somewhere in space. This campus has large antennas of
32-metre and 18-m diameter to track planetary projects such as the
Mars and the lunar missions. India's first Lunar mission, “Chandrayan
I” was controlled from here and the Mars orbiter mission that is
likely to take off in October or early November so as to leave
Earth’s atmosphere by November 27, would also be controlled from
here.

A new facility was commissioned at this
complex this week, that would soon become the nerve centre or the
hub, of India's forthcoming navigational satellite constellation,
called as Indian Regional Navigation Satellite System (IRNSS), which
would be an independent regional navigation satellite system designed
to provide position accuracy better than 10m over India and the
region extending about 1500 kms around India. It will provide an
accurate real time Position, Navigation and Time (PNT) services to
users on a variety of platforms with 24x7 service availability under
all weather conditions.

In simple terms, IRNSS would be an
independent positioning system like GPS that will give data on the
position, navigation and time of persons or objects to a range of
users. This nerve centre would become truly operational, when India's
first regional navigational satellite, R1A, gets launched at
midnight on June 12,2013. The satellite will be launched on the PSLV
rocket from Sriharikota, on east coast of India.

This satellite would be joined by 6
more satellites to be launched within next three years to form the
IRNSS constellation that will give data on the position, navigation
and time of persons or objects to a range of users.

This facility houses a high stability
atomic clock to keep precise time and reference, pool and synthesise
navigational messages and coordinate 21 ground stations across the
country. The constellation of 7 satellites in space will give
positional accuracy of within 10 meters. Its users will be from
aerospace, military, all transport systems, geo information of the
Survey of India and also individual users. Two basic services would
be available as standard Positioning Service (SPS,) one for common
civilian users and second one for Restricted Service (RS) for special
authorized users.

Satellites of the IRNSS constellation
would be identically configured with each spacecraft weighing 1425
kg. The navigation software for IRNSS is being indigenously developed
at ISRO.